Casing head for oil wells



Dec. 25, 1928.

- H.-S. HAYNES ET AL CASING HEAD FOR OIL WELLS Filed Nov. 11, 1925 s m m x N mt M .wHm. w MWL A M Patented Dec. 25, 1928.

UNITED STATES PATENT OFFICE.

HUGH SCOTT HAYNES AND WILLIAM L. ALEXANDER, 0F TAMPICO, MEXICO, ASSIGN- ORS OF ONE-THIRD T0 GEORGE E. PADDLEFORI), OF TAMPICO, .TAMAULIPAS,

MEXICO.

CASING HEAD FOR OIL WELLS.

Application filed November This invention relates more particularly to a casing head construction adapted for securely connecting together at the top of a well a plurality'of strings of well casing in gas or fiuid tight relation to each other.

It is of the objects of the invention, first to provide a novel form of casin head for securely connecting in concentric relation to each other a plurality of strings of well casing in gas and fluid tight relation to each other. Second, to provide a casing head that will effectually resist, if necessary, unusual pressures developed in the drilling or operating of oil or gas wells.- Third, to provide a construction in which it is possible'to connect several strings of casing in less time than by existing methods. Fourth, to provide a casing head in which a string of well casing may be readily hung from the upper end with casing shoe OK the bottom of the well, and whereby it is also possible to cement the string on the bottom, take the stretch thereon, and then secure the string in the head without danger of releasing the stretch. Fifth, to provide a casing head construction in which it is possible to land a plurality of strings of well casing within a small space, that is inexpensive to manufacture, easily handled, and which has no bolts or other small parts that are easily lost or'damaged.

This disclosure is to be regarded as descriptive only and not as restrictive or limitive of the invention, of which obviously an embodiment may be constructed including many minor modifications without departing from the eneral scope herein indicated and hereina ter claimed. 7

Other objects and advantages will become apparent from the following specification, reference being had to the drawings accompanying the same, in which:

Fig. 1 is a central vertical section through the casing head with a plurality of strings of casings secured thereto.

Fig. 2 is a plan view.

Fig. 3 is a transverse section taken on line 33 of Fig. 1. I

Fig. 4 is an enlarged sectional detail of one of the bushing seats.

7 Referring now more particularly to the drawings, and especially to Fig. 1, 5 designates the upper stand of an anchored well casing provided with the usual coupling collar 6 at the top thereof. In screw thread- 11, 1925. Serial No. 68,415.

ed engagement with the collar 6 is a cylindrical head body 7 provided with a bore 8 in its lower end that opens into an enlarged counter bore 9 at the top thereof, the upper end of the head being threaded exteriorly for the reception of a master valve of usua construction (not shown).

As illustrated in the drawings, three strings of casing are shown connected to the casing head body, the means for connecting the 8% inch casing 10, preferably consisting of a head bushing 11, cylindrical in form, interiorly threaded on its lower end for the reception of the casing 10, and having an enlarged bore 12 at its upper end, the external surface being threaded left hand for engagmg the internal threaded lower end of a locking ring 13 when the parts arein an assembled form. Head bushing ll is provided justabove its lower end with an annular bevelled seat 14 that engages a similar seat 15 formed on the lower circular end of the .body 7, a copper gasket 16 insuring a gas and fluid tight seat.

The locking ring 13 engages the left hand thread of thebushing 11, and its lower circular end engages the circular seat 17 formed by the enlarged counter bore 9 of the head member 7, a copper gasket 18 being mounted therebetween to form a gas and fluid tight seat. The upper end of the locking ring 13 is provided with spanner wrench sockets 19 for screwing the ring downwardly against its seat, and at the same time drawing the bevelled seat 14 formed on the bushing into engagement with the seat 15 of the head body.

From the above it will be apparent that the casing 10 will be connected to thehead in gas tight relation, the double seats efi'ectually preventing any leakage of gas or oil therethrough.

The string of 6 inch casing 20, as shown in the drawings, is connected in gas and fluid tight relation to the first two strings of casing by the head bushing 21, that is of tubular form intcriorly threaded at its lower end for the reception of the casing 20, its upper exterior end being provided with a left hand thread for the reception of a 6% inch circular locking ring 22. The bore of the 8 inch locking ring 13 is enlarged to form a flat circular seat 23 against which the lower end of the ring 22 bears, a copper gasket 24 disposed on the seat serving to form an absolutely gas and fluid tight joint. A short distance above the lower end of bushing 21 is formed an annular bevelled seat 25 to form a circular space for the reception of a tubular seat bushing 26 provided on its upper edge with spanner wrench sockets 27 for the purpose of inserting or removing the same. The exterior upper surface of this bushing is provided with a right hand threadthat engages a similar thread formed on the enlarged portion of the bore of bushing 11 to hold the same in gas tight relation with the bevelled seat 25, a copper gasket 28 serving to form a fluid tight vjoint. It will be noted that when the bushing 26 has been seated and the locking ring 22 tightened that the bevelled seat 25 of bushing 21 will be drawn in gas and fluid tight engagement with the lower bevelled end of the bushing 26. The upper interior end of bushing 21 is threaded for a standard casing when it is desired to remove the casing from the well.

The operation of assembling an 8% inch casing within a 10 inch casing is as follows: Assuming that the 8% inch string 10 has been cemented at the bottom of the well, and that the top collar of said casing (not shown) lies a short distance below the collar 6 of the anchored string 5, a distance is measured between the bottom of the head bushing 11 and the top of the 8% inch collar. A nipple (not shown) is then cut to this measurement, making an allowance for the threads and the amount of stretch itois desired to take in the string of casing. The 8% inch locking ring 13 and the head body 7 are then slipped over a joint of said casing, screwing the top end of the head bushing 11 onto the bottom end of the above mentioned joint of casing, and then screwing the 8% inch nipple cut to measure as above set forth into the bottom end of the 8% inch head bushing 11. These connections now suspended on a joint of 8% inch casing hanging on elevators in derrick are then placed within the 10 inch string 5, and the bottom end of the 8% inch nipple is screwed into the top collar of the 8% inch cemented string. The head body 7 is then screwed into the 10 inch collar 6 after which a stretch is taken in the 8% inch string 10 until the bevelled shoulder 14 on the outer surface of the 8% inch head bushing 11 en ages the bevelled seat 14 on the bottom end of the head body 7. The locking ring 13 is then screwed down on the outside of the 8% inch head bushing 11 until the bottom edge of the ring engages the flat seat inside of the head body 7. The 8% inch joint casing which was screwed (for purposes of handling connections only) into the top of the 8% inch head bushing 11 is then backed out, and a master valve (not shown) is screwed on the top of: the head body 7, together with such other connections fitted above the valve as may be found desirable.

In landing a string of 6% inch casing 20 inside of the 8% inch casing 10, substantially the same method is employed as in landing the 8% inch string, with this exception, that it is necessary to insert the 6% inch seat bushing 26 in the top of the 8% inch head bushing 11 to form the bevelled seat for the shoulder 25 formed on the exterior surface of the 6% inch head bushing 21 to seat on. The locking ring 22 is then screwed down on the outside of the 6% inch head bushing 21, its bottom edge forming a gas tight seat when it engages the flat shoulder 23 formed on the inside of the locking ring 13.

Should it be desired for any reason to set astring of- 6% inch casing inside of the anchor string 5 without connecting to an 8% inch string, this can be accomplished by leaving parts 7, 13, and 11 in place, and then setting the string of 6% inch casing as above described.

It will be noted that the 8% inch locking ring 13 and the 6% inch locking ring 22 are provided with left hand threads in order that when any connection is made into the top of the head bushing 21, there will be no danger of backing the bushing out of the locking ring.

Should a 11 or 12 inch casing be used as an anchor string the casing head above described can be used by merely changing the outside dimensions of the casing head body 7 at its lower end. When it is desired to connect to it or vent between the various strings of easing it can be accomplished in the following manner: To vent between the anchor string 5 and the 8% inch string the anchor string collar 6 may be drilled and tapped between the upper end of the casing and the lower end of the casing head body 7 Should it be found for any reason undesirable to vent in the above manner, a special tapped steel collar (not shown) can be used to take the place of the standard collar on the anchor string. When it is desired to vent between the 8% inch and the 6% inch strings of easing, the vent plug 30 in the lower part of the casing head body 7 may be removed and a hole drilled through the 8% inch head bushing 11 before the 6% inch head bushing 21 is installed.

It will be apparent to those who are familiar with oil well 0 erations, that the casing head above descri ed possesses all of the essential requisites of other well known constructions, without their disadvantages, this being clearly apparent in the construction known to oil operators as the swinging nipple carrying a control valve with a Braden head attached thereto. This latter construction, which is exceedingly complicated, carries V-shaped rings designed to compress and expand inside when the bolts are tightened to form a fluid tight joint against the pipe. Such joints have been found to be neither satisfactory or practical, as under pressure they are liable to leak. Moreover a Braden head is extremely expensive to manufacture, cumbersome to handle, and further they utilize about seven feet of space under the derrick floor, while our-improved head onl occu ies a space ap proximately not excee ing fi teen inches, all the elements being disposed below the disks of the master valves.

By means of our construction any number of strings of various sized well casings may be quickly secured in position within the anchored casing, the bushing, locking rings, and the gasket seats insuring perfect gas and fluid tight joints between the several strings connected to the casing head. When different sizes and weights of casing are employed to suit varying conditions existing in widely separated oil fields, the heads may be readily changed to adapt them for such conditions.

What we claim is:

1. A casing head construction comprising a body member provided with an interior annular seat, adapted to be detachably secured to the upper end of a well casing, a locking ring disposed within said head and engaging said annular seat, and a casing head bushing for connecting a string of cas ing detachably secured to said locking ring, said bushing'provided with an annular seat adapted to engage the casing head to form a gas tight joint therebetween.

2. In a casinghead for oil wells, a cylindrical body member provided with a fluid tight seat, adapted to be secured to a string of well casing, a tubular head bushing provided with a seat engaging the seat of the body member, means formed on said bushing for connecting a string of casing thereto, and a tubular locking ring threadingly seof the head bushing and the body member into gas and fluid tight engagement.

3. In a casing head for oil wells,- a cylindrical body member provided with bores of different diameters, the juncture of said bores forming an annular seat, adapted to be secured to the upper end of a string of Well casing, a tubular head bushin having a seat formed on its external sur ace disposed within said body member, said bushing adapted to connect a string of well casing to the body member, and a locldng ring member adjustably secured to the upper end of said head bushing within said body member, the lower end of said ring engaging the annular seat of the body member, the external seat of the head bushing engaging a like seat formed on the body member, whereby when the locking ring is tightened the seats formed on the body member and on the head bushing will engage to form fluid tight joints between the strings of easing.

In witness that we claim the foregoing we have hereunto subscribed our names this first day of October, 1925.

H. SCOTT HAYNES.

L. ALEXANDER.

cured to said bushing for forcing the seats 

